The money will be earmarked mostly for the recuperation of agricultural land which was destroyed by torrential rains and mudslides caused by the storm in the two Central American countries last week, it said in a statement.
Portugal will formally inform El Salvador and Guatemala of the aid offer at a two-day summit of Spanish-and-Portuguese-speaking leaders which got underway in Salamanca, Spain on Friday, the statement added.
Stan lashed Central America and Mexico with days of relentless rain starting October 1, triggering floods and landslides.
As many as 2,055 died in flooding and mudslides in hardest-hit Guatemala. Seventy-two other were killed in El Salvador, 42 in Mexico and 11 in Nicaragua.